look for steven on the east. talk to him. battle kecleon. he will give you a "Devon scope". go to the sixth gym. use Devon scope on the invisible barrier. it is a kecleon but it will flee. then you are accessible to the sixth gym.good luck getting the sixth badge. (tip: bring electric Pokemon along.)
You beat the 6th Gym Leader Winona at the Fortree Gym. To get to the Gym you need the Silph Scope which Steven will give you. If you follow the path that goes east of town, you should bump into him I think.
Defeat Sabrina in Saffron Gym. Her speciality is Psychic Pokémon, so Ghost/Ground types are useful. Refrain from using Fighting or Poison type Pokémon or moves against her.
You Have to surf to cianwood city from olivine and the gym should be in cianwood
you have to battle the gym leader (isn't it obvious?)
You have to beat Erika the nature lover in the fourth gym in Celadon City. Then you get the fourth badge, the Rainbowbadge
you battle your father
you defeat the gym
Go to aquas base in Lilycove
with electric and fire type Pokemon
Go beat the 6th gym leader ^^, that is in Fortree City.
It depends which ones are you looking for. The 8th Badge is in Sootopolis, The 7th badge is in Mossdeep, The 6th Badge is in Fortree, The 5th badge Is your dad in emerald it is found at Petalburg, the 4th Badge is in Fallabore, The 3rd badge is in Mauville, The 2nd badge is in Dewford, The 1st badge is in Rustboro.
at the gym
Go to the Pokemon league.
Dewford Town.
Destroys picachew
the ground gym
You can get the 6th badge by defeating your father in petalburg.
Beat the gym leader
you travel to lavavine town